Means for separating the body of oil of a transformer and the body of oil of a tap-changing switch

ABSTRACT

The body of oil in which a transformer is immersed and the body of oil in which tap-changing switching means are immersed are separated by a plurality of stacked, spaced insulating plates maintained by fixed intermediate spacers in the spaced positions thereof.

' United States Patent [191 Bleibtreu MEANS FOR SEPARATING THE BODY OF OIL OF A TRANSFORMER AND THE BODY OF OIL OF A TAP-CHANGING SWITCH [58] Field of Search 336/58, 94, 105, 150, 192; 174/18, 151, 152; 317/157.6

[ Apr. 16, 1974 [56] References Cited UNITED STATES PATENTS 3,344,229 9/1967 Wilk 174/18 X 2,611,002 9/1952 James 174/18 2,438,008 3/1948 Hoop 174/151 Primary Examiner-Thomas J. Kozma Attorney, Agent, or Firm--Erwin Salzer [57] ABSTRACT The body of oil in which a transformer is immersed and the body of oil in which tap-changing switching means are immersed are separated by a plurality of stacked, spaced insulating plates maintained by fixed intermediate spacers in the spaced positions thereof.

7 Claims, 2 Drawing Figures BODY OF OIL OF TAP-CHANGING SWITCH BODY OF on. OF TRANSFORMER PATENTEUAPR is .914 3.805205 BODY OF on. OF 3 14 14cm TAP-CHANGING 5 L SWITCH BODY OF on. 0 25% TRANSFORMER MEANS FOR SEPARATING THE BODY OF OIL OF A TRANSFORMER AND THE BODY OF OIL OF A TAP-CHANGING SWITCH BACKGROUND OF THE INVENTION In the design of tapped regulating transformers it is common practice to arranged the transformer proper, i.e. its core and windings, in a first oil-filled tank, and to arrange the tap-changing switching means, particularly the transfer switch, in a second oilfilled tank. Both tanks are mechanically tied together to form a structural unit. Means in the nature of a bushing provide a well insulated electric connection from the space inside the first or transformer tank to the space inside the second or switching means tank. Generally the transformer tank is provided with an opening or window closed by a plate of electric insulating material which forms a partition between both tanks. This plate insulates electric connector rods at an elevated poetntial projecting transversely through it from the transformer tank to the switching tank which are at another or ground potential. This plate further forms a mechanical support for the aforementioned connector rods. The size or area of such plates must be relatively large. Since the transformer tanks are evacuated, plates of the kind under consideration are subjected to very high pressures. In view of the high pressures to which such plates are subjected, and in view of the severe dielectric duty imposedupon them, their thickness must be high, resulting in high cost. An insulating plate having an area of about 1 square yard calls for a thickness of about 2". The cost of manufacturing insulating plates having dimensions of the above order of casting resins are virtually prohibitive. The conventional way of manufacturing the plates by laminating relatively thin plates to the required ultimate thickness in the order of 2" is not readily feasible because laminates of the sizes under consideration have not the required high dielectric integrity, but tend to be subject to dielectric interlaminate breakdowns.

The primary object of this invention is, therefore, to

provide cost effective insulating means for separating the body of oil of a transformer and the body of oil of tap-changing switching means and forming bushings allowing to conductively interconnect the transformer and its tap-changing switching means.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a section across a structure embodying the present invention; and

FIG. 2 is a side elevation of the structure shown in FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENT In the drawings reference numeral 2 has been applied to indicate a first body of insulating oil for submersing therein a regulating transformer (not shown), and reference numeral 3 has been applied to indicate a second body of insulating oil for submersing therein tapchanging switch means (not shown), operatively related to the transformer in the first body of oil 2. Composite structures of this nature are well known in the art and are disclosed more in detail in the patents which are identified below: US. Pat. No. 3,174,097 to A. Bleibtreu, Mar. 16, 1965 for TRANSFER SWITCH FOR TAP CHANGERS FOR REGULATING TRANS- FORMERS, and A. Bleibtreu, US. Pat. No. 3,396,254, Aug. 6, 1968 for ARRANGEMENT FOR AVOID- ING EDDY CURRENT LOSSES IN TRANSFER SWITCH AND SELECTOR SWITCH UNITS WITH INTERPOSED GEAR DRIVE. These two patents disclose more in detail switch means applied for performing tap-changing operations, and reference may be had to these patents in regard to such switch means with which the present invention is not directly concerned.

Reference numeral 6 has been applied to indicate;-

first plate or partition separating the bodies of oil 2 and 3. The first plate or partition 6 is provided with an aperture which is closed by insulating means generally designated by reference numeral 1. It will be apparent from the above that first plate or partition 6 is the side wall of an oil tank for housing a high-voltage transformer. Plate or partition 6, supports a rectangular frame 4 surrounding an area coextensive with the aforementioned aperture in the former. As indicated in FIG. 1 frame 4 may be welded to plate 6. The side of frame 4 facing the body of oil 2 is provided with a groove receiving a gasket 5.

The insulating means I for closing the aperture in plate 6 consist of a plurality of stacked spaced insulating plates ll, 12, 13 and fixed spacers 8 between contiguous said plates maintaining the spacing thereof. Screw-threaded studs 7 project through some of spacers 8 and through plates 11, 12, 13 and affix insulating plates 11, 12, 13 to the frame 4 and the first plate or partition 6, respectively. Reference numeral 9 has been applied to indicate connecting rods for establishing electric connections between the transformer in the body of oil 2 and switch means in the body of oil 3. Connecting rods 9 project through some of spacers 8 and through insulating plates 11, I2, 13. The lower end of rods 9 (as seen in FIG. I) is immersed in the body of oil 2 and the upper end 14 of rods 9 (as seen in FIG. 1) is immersed in the body of oil 3 and engages a cooperating contact 14a. Parts 14, 14a form disconnects. Reference numeral 10 has been applied to indicate cable terminals connecting taps of a tapped transformer winding to rods 14 and contacts 14a. Top insulating plate 11 abuts against the planar surface of frame 4, and gaskets l5 surrounding the upper ends 14 of rods 9 provide seals between the bodies of oil 2 and 3. Rods 9 are preferably provided with screw-threads at the points thereof projecting through plates 11,12,13 to increase the dimensional stability of structure 1. It will' be noted that the hermetic separation of the bodies of oil 2,3 is effected only by one or the uppermost plate 11 of electric insulating material, plates 12 and 13 not being sealing means but only means to increase the dimensional stability of the composite structure separating the bodies of oil 2,3 from one another. Plates 12 and 13 are provided with apertures or bores 16 allowing circulation of oil transversely across the planes of plates 12 and 13.

The stack formed by spaced relatively thin insulating plates 11,12,13 and intermediate layers of oil has a high dielectric strength and can readily be manufactured at moderate cost. lts dimensional stability is very high, and sufficient to establish an effective hermetic seal between the evacuated transformer tank and the nonevacuated switching means tank. Parts 8,9,11,12,13 are multipurpose means for closing the aperture in plate 6 and separating the bodies of oil 2,3 and for allowing the flow of currents from the space inside of, to the space outside of, the transformer tank while maintaining a high insulation level between parts 9 at elevated potentials and any part at ground potential.

I claim as my invention:

1. A tap-changing transformer structure including a. a first plate separating a first body of oil for immersing a tapped transformer and a second body of oil for immersing tap-changing switching means, said plate being provided with an aperture; and

b. insulating means for closing said aperture including a plurality of stacked, spaced insulating plates and fixed spacers between contiguous said plates maintaining the spacing thereof.

2. A tap-changing transformer structure as specified in claim 1 including screw-threaded studs projecting through some of said spacers and through said plurality of plates and affixing said plurality of plates to said first plate.

3. A tap-changing transformer structure as specified in claim 1 including a plurality of rods for establishing electric connections projecting through some of said spacers and through said plurality of plates, each of said plurality of rods having one end immersed in said body of oil and said transfonner and having another end immersed in said body of oil of said tap-changing switching means.

4. A tap-changing transformer structure as specified in claim 1 wherein one single of said plurality of plates separates said body of oil of said transformer and said body of oil of said tap-changing switching means, all the other plates of said plurality of plates being immersed on both sides thereof in said body of oil of said transformer.

5. A tap-changing transformer structure as specified in claim 1 wherein said aperture of said first plate is surrounded by a planar frame affixed to said first plate, one of said plurality of plates abuts under pressure against said planar frame, and a gasket is interposed between said planar frame and said one of said plurality of plates.

6. A tap-changing transformer as specified in claim 1 wherein some of said plurality of plates are provided with apertures allowing circulation of oil transversely across the planes of said some of said plurality of plates.

7. In combination a. an oil tank containing a first body of oil for receiving a transformer having a tapped winding, said tank having a wall portion provided with an aperture of relatively large size;

b. a second body of oil outside of said oil tank in engagement with said wall portion; and

c. multiple purpose means for closing said aperture, separating said second body of oil outside said tank from said first body of oil inside said tank and forming bushing means allowing the flow of electric currents from the space inside said tank to the space outside said tank, said multiple purpose means including a plurality of spaced insulating plates alternating with layers of oil, a plurality of spacers for maintaining a predetermined fixed spacing between each of said plurality of insulating plates, and a plurality of connector rods projecting transversely across said plurality of plates and said layers of oil, each of said plurality of connector rods being affixed to each of said plurality of plates.

130-1050 UNITED STATES PATENT OFFICE 1 CELRIIFICATE. (IQRRECTION Patent No. 3,805,205 A v I Dated Apr. 16,1974

' Alexander Bleibtreu Inventor(s) V I It is certified that error appears in the. above-identified patent and that said-Letters Patent are hereby corrected as shown below:

'Cover page, left column, line 5 "841 Regensbufy should read 84 Regensburgline 10 "May 26,1972 Germany .2225072" Should readr-May 25,1972 Germany Signed and Sealed this ISEALI m f November 1975 Arrest:

RU'FH C. MASON Alrvsfing Officer I C. MARSHALL DANN A umml'sximu'r nfPare/m um] Trm/cmurlcv P0-1050 UNITED STATES PATENT OFFICE CiLRlIFICATE. OF CORRECTION Patent NO. 3,805,205 Dated Ap 16,1974

Inventor(s) Alexander Bleibtreu.

It is certified that error appears in the. above-identified patent and that said Letters Patent are hereby corrected .as shown below:

Cover page, left column, line 5 "841 Regensbur y" should read "84 Regensburg--; line 10 "May 26,1972 Germany .2225072" should read- --May 25, 1972 Germany P 07 2l0 l 51=gncd and Sealed this SEAL} fWenty-fifzh Of November 1975 Arrest:

RUTH C. MASON MARSHALL DANN vmmmsinm'r (If Parents and Tr d o L J 

1. A tap-changing transformer structure including a. a first plate separating a first body of oil for immersing a tapped transformer and a second body of oil for immersing tapchanging switching means, said plate being provided with an aperture; and b. insulating means for closing said aperture including a plurality of stacked, spaced insulating plates and fixed spacers between contiguous said plates maintaining the spacing thereof.
 2. A tap-changing transformer structure as specified in claim 1 including screw-threaded studs projecting through some of said spacers and through said plurality of plates and affixing said plurality of plates to said first plate.
 3. A tap-changing transformer structure as specified in claim 1 including a plurality of rods for establishing electric connections projecting through some of said spacers and through said plurality of plates, each of said plurality of rods having one end immersed in said body of oil and said transformer and having another end immersed in said body of oil of said tap-changing switching means.
 4. A tap-changing transformer structure as specified in claim 1 wherein one single of said plurality of plates separates said body of oil of said transformer and said body of oil of said tap-changing switching means, all the other plates of said plurality of plates being immersed on both sides thereof in said body of oil of said transformer.
 5. A tap-changing transformer structure as specified in claim 1 wherein said aperture of said first plate is surrounded by a planar frame affixed to said first plate, one of said plurality of plates abuts under pressure against said planar frame, and a gasket is interposed between said planar frame and said one of said plurality of plates.
 6. A tap-changing transformer as specified in claim 1 wherein some of said plurality of plates are provided with apertures allowing circulation of oil transversely across the planes of said some of said plurality of plates.
 7. In combination a. an oil tank containing a first body of oil for receiving a transformer having a tapped winding, said tank having a wall portion provided with an aperture of relatively large size; b. a second body of oil outside of said oil tank in engagement with said wall portion; and c. multiple purpose means for closing said aperture, separating said second body of oil outside said tank from said first body of oil inside said tank and forming bushing means allowing the flow of electric currents from the space inside said tank to the space outside said tank, said multiple purpose means including a plurality of spaced insulating plates alternating with layers of oil, a plurality of spacers for maintaining a predetermined fixed spacing between each of said plurality of insulating plates, and a plurality of connector rods projecting transversely across said plurality of plates and said layers of oil, each of said plurality of connector rods being affixed to each of said plurality of plates. 